DDSCAT has been updated since this question was posted, Remote simulations now use less memory than previously when requesting a Nearfield generating simulation (this is typically the most storage-intensive type of simulation).

In detail, Remote simulations send out only a Nearfield calculation for the wavelength with the greatest Light Extinction value. Local runs of DDSCAT will still inefficiently calculate a Nearfield at every wavelength, thus generating a lot of storage usage.

This may resolve your issue with DDSCAT, alternatively you can send a Ticket to request more storage space from the Nanohub administrative team.